Switches with integral overcurrent protection components

Abstract

Switches with integrated overcurrent protection elements are described. The overcurrent protection elements can include a bimetallic structure which is configured to move between a first shape and a second shape in response to heating. The overcurrent protection element can be rotationally coupled to a rotary knob in some embodiments. In other embodiments, the overcurrent protection element can be fixed, and the rotary knob can be connected to one or more rotatable conductive structures within the rotary switch.

What is claimed is: 
     
       1. A rotary switch including an integrated overcurrent protection device, the switch comprising:
 a housing; 
 a first terminal extending into the housing and electrically connected to a first terminal contact; 
 a second terminal extending into the housing and electrically connected to a second terminal contact; 
 a switching mechanism, comprising:
 a knob rotatable with respect to the housing; and 
 a rotatable conductive element located within the housing and rotationally coupled to the knob to rotate in response to rotation of the knob, the rotatable conductive element comprising a bimetallic element configured to change shape from a first shape to a second shape in response to electrical current above a specified limit, the rotatable conductive element rotatable between a first angular orientation in which the rotatable conductive element is electrically connected to the first and second terminal contacts and a second angular orientation in which the rotatable conductive element is not electrically connected to at least one of the first and second terminal contacts; and 
 
 a reset mechanism operable independent of operation of the switching mechanism, the reset mechanism configured to change the shape of the bimetallic element from the second shape to the first shape, wherein the reset mechanism comprises:
 a reset button concentric with a center post and the knob, the reset button extending through a through-hole in the knob, and 
 a reset plate operably connected to the reset button, wherein depressing the reset button forces the reset plate against the bimetallic element to move the bimetallic element to the first position, and wherein the bimetallic element will remain in the second position in the absence of electrical current above the specified limit until the reset mechanism is used to change the shape of the bimetallic element from the second shape to the first shape. 
 
 
     
     
       2. The rotary switch of  claim 1 , wherein the bimetallic element is configured to change shape between the first shape in which the bimetallic element is electrically connected to the first and second terminal contacts when the overcurrent protection element is in the first angular orientation, and the second shape in which the bimetallic element is curved such that the bimetallic element is not electrically connected to at least one of the first and second terminal contacts when the overcurrent protection element is in the first angular orientation. 
     
     
       3. The rotary switch of  claim 1 , wherein the bimetallic element is configured to change shape between the first shape in which the bimetallic element is electrically connected between the first and second contacts within the housing and the first shape in which the bimetallic element is not electrically connected to at least one of the first and second contacts within the housing. 
     
     
       4. The rotary switch of  claim 1 , wherein the reset button is biased away from the bimetallic element by a spring. 
     
     
       5. The rotary switch of  claim 1 , wherein operation of the switching mechanism does not cause the bimetallic element to change from the second shape to the first shape. 
     
     
       6. The rotary switch of  claim 1 , wherein the bimetallic element requires mechanical interaction to return to the first shape. 
     
     
       7. A rotary switch including an integrated overcurrent protection device, the switch comprising:
 a housing 
 a first terminal extending into the housing and electrically connected to a first terminal contact; 
 a second terminal extending into the housing and electrically connected to a second; 
 a knob rotatable with respect to the housing; 
 an overcurrent protection element located within the housing and rotationally coupled to the knob to rotate in response to rotation of the knob, the overcurrent protection element rotatable between a first angular orientation in which the overcurrent protection element is electrically connected to the first and second terminal contacts and a second angular orientation in which the overcurrent protection element is not electrically connected to at least one of the first and second terminal contacts, wherein rotation of the knob to change the angular orientation of the overcurrent protection element does not reset the state of the overcurrent protection element; and 
 a reset mechanism configured to reset a state of the overcurrent protection element without rotating the knob, wherein the reset mechanism comprises a button concentric with the knob and extending through a through-hole in the knob. 
 
     
     
       8. The rotary switch of  claim 7 , wherein the overcurrent protection element comprises a bimetallic element configured to deform from a first shape to a second shape in response to Joule heating. 
     
     
       9. The rotary switch of  claim 8 , wherein the bimetallic element requires mechanical interaction to return to the first shape. 
     
     
       10. The rotary switch of  claim 8 , wherein the bimetallic element will remain in the second shape in the absence of Joule heating until the reset mechanism is used to return the bimetallic element to the first shape. 
     
     
       11. A rotary switch including an integrated overcurrent protection device, the switch comprising:
 a housing; 
 a first terminal extending into the housing and electrically connected to a first terminal contact; 
 a second terminal extending into the housing and electrically connected to a second terminal contact; 
 a knob rotatable with respect to the housing; 
 a rotatable conductive element located within the housing and rotationally coupled to the knob to rotate in response to rotation of the knob, the rotatable conductive element rotatable between a first angular orientation in which the rotatable conductive element is electrically connected to the first and second terminal contacts and a second angular orientation in which the rotatable conductive element is not electrically connected to at least one of the first and second terminal contacts, the rotatable conductive element comprising a bimetallic element configured to change shape in response to electrical current above a specified limit, wherein the bimetallic element is configured to change shape between a first position in which the bimetallic element is electrically connected to the first and second terminal contacts when the rotatable conductive element is in the first angular orientation and a second position in which the bimetallic element is not electrically connected to at least one of the first and second terminal contacts; and 
 a reset mechanism configured to reset the bimetallic element from the second position to the first position, wherein the reset mechanism comprises a reset button concentric with a center post and a reset plate operably connected to the reset button, wherein depressing the reset button forces the reset plate against the bimetallic element to move the bimetallic element to the first position, and wherein the reset button is concentric with the knob and extends through a through-hole in the knob. 
 
     
     
       12. The rotary switch of  claim 11 , wherein the bimetallic element will not return to the first position without use of the reset mechanism to reset the bimetallic element from the second position to the first position. 
     
     
       13. The rotary switch of  claim 11 , wherein rotation of the knob to change the angular orientation of the rotatable conductive element does not change the shape of the bimetallic element.